A moving body system is known, which includes a magnetic pole path in which a plurality of pairs of magnetic poles including a north pole and a south pole are arranged and a moving body having a linear motor. In the moving body system of this type, the linear motor is driven by the magnetic interaction with magnetic flux of the magnetic pole path, whereby the moving body moves along the magnetic pole path. Japanese Unexamined Patent Publication No. 2014-217077 discloses a moving body system of this type.
In the moving body system of this type, a magnetic pole absent section that lacks a magnetic pole may exist in the magnetic pole path.
In this respect, in the moving body system described in Japanese Unexamined Patent Publication No. 2014-217077, a moving body includes two linear motors, two magnet absence detection sensors (for example, photosensors) respectively corresponding to the two linear motors, and two position detection sensors (for example, Hall elements) respectively corresponding to the two linear motors. When one of the magnet absence detection sensors detects that one of the linear motors is positioned at a magnetic pole absent section, the moving body switches to the other linear motor thereby enabling continuous drive. Furthermore, when it is detected that one of the position detection sensors is positioned at a magnetic pole absent section, the moving body switches to the other position detection sensor, thereby enabling continuation of the position detection of the moving body.
We devised a moving body that includes a single position detection sensor to detect the position of the moving body and one electrical angle detection sensor for each linear motor to detect an electrical angle to control the drive of the linear motor. In this moving body, when one of the position detection sensor and the electrical angle detection sensors is positioned at a magnetic pole absent section, the position of the moving body or the electrical angle of the corresponding linear motor is unable to be detected.
It could therefore be helpful to provide a moving body in which even when any one of the position detection sensor and the electrical angle detection sensors is positioned at a magnetic pole absent section, the position of the moving body or the electrical angle of the corresponding linear motor can be detected.